The world of mathematics.
For a good measure.
We can measure many different things.
Pressure.
Volume.
Time.
Temperature.
Weight.
We measure to be able to describe accurately and to help us understand and observe different
behaviors.
For example, what would you measure to compare yourself with another person of your age?
Comparison of people.
What would you measure?
What units would you use?
Weight is a good choice and to measure it you can use units in kilograms or pounds.
How could we measure the height?
This line has been drawn one meter above the level of the floor.
As you can see, Nick has a height of more than one meter.
In fact, he is more than one and a half meters.
Also Susie.
If we only have the meter as a unit of measurement, then we could say that everyone measures
approximately two meters high.
But what about Chris Greener?
If we take measurements only in meters, then Chris would also measure two meters high.
But if you want to find the tallest man in the world, you need to take measurements in
a more precise way.
And who is the tallest man in the world?
The tallest man in the world is a young man from Pakistan who measures a little more than
seven feet.
With eight inches.
This is about two meters thirty-four centimeters.
When measuring the height of people with greater precision, it is not enough to approximate
only in meters.
Think of a reason to measure height.
With what precision would you try to measure?
Would you approximate in inches?
In half inches?
In centimeters?
In millimeters?
How could you make sure that the measurement is exact?
The height of Humberto seems to be one meter seventy-nine centimeters, that is, one point seventy-nine
meters.
But that is in approximate centimeters.
He really measures one point seven hundred and ninety-three meters.
Why doesn't he say one point seven hundred and ninety-three?
When Humberto returned to the clinic early the next day, he measured one point seven hundred
and ninety-five meters.
Can we grow two millimeters during the night?
In a certain sense, yes.
When you are young and you are still in the stage of growth, the discs that separate the
vertebrae in the spine are flexible and are slightly pressed by the descending force
of gravity.
When you are lying down, your spine separates slightly.
And when you get up in the morning, you can measure up to five millimeters more than what
you will measure hours later.
So if you are doing a survey of the growth of people, you will always need to measure
each one at the same time of the day and be more accurate, using millimeters and not
only approximate meters, but not only is the growth measured.
Length.
Take this bar.
Imagine that we need to use it as part of an exact manufacturing process.
What measurement would you say you have?
We could say that its length is between three and four meters.
Once again, using only the meter as a measurement unit, we would say that the length of the
bar is three meters.
Suppose that now we divide one meter into ten parts called tenths.
Using this division, the length of the bar is three point two meters, but it actually
measures something more than three point one.
Subdividing each tenth into ten parts, we would have the length of the bar close to
three point sixteen meters.
Following the process, we divide each part into ten and thus we obtain the millimeters.
Therefore, the length is three point one hundred and sixty-four meters.
Do you think this measurement is accurate enough?
We could go into more detail, but the important point is to know when we have reached the
level of precision necessary.
In modern industries, it is necessary to use highly automated production machines in order
to maintain a consistent level of precision.
But even the components made by machines may need careful reviews by the hand of man.
Andy Walker uses very precise measurements to do this.
They are used in critical stages of the production process to detect any error that may appear
in the system.
The measurements provide the differences between the theoretical measurement and the real measurement.
The work plan shows a measurement of thirty-seven millimeters, with a tolerance margin of more
or less zero point twenty-five millimeters.
The external diameter is theoretically thirty-seven millimeters, but how close should it be to
this measurement?
The thirty-seven millimeter diameter cannot decrease more than point twenty-five millimeters,
and it cannot increase more than point twenty-five millimeters, so the diameter can only oscillate
between thirty-six point seventy-five millimeters and thirty-seven point twenty-five millimeters.
When placing an aquel in your house, Andy needs much less precision.
It is enough for you with the sixteenth of an inch or the millimeters of a meter.
When you measure something, you must say how much precision you need and how you can achieve it.
The weight of this trailer is twelve thousand four hundred and twenty kilograms and the kilo
is used as a weight measurement.
The time the winner takes is ten point forty-two seconds, this is using up to hundredths of
a second.
This boat is about to cross the final line of a race around the world that lasted several
months.
How accurate should the time it took on its journey be measured?
How exactly can you measure it?
What other measurements can you think of?
What units could you use and what do you think you have measured with the correct precision?
Thank you.